Chris Anderson invited Bill and Melinda Gates to the TED2014 stage for what turned out to be a personal and charming Q&A. This is an edited version of that conversation.

Anderson began with the provocation, “On the basis that a picture’s worth a thousand words, I asked them to dig from their archive to explain what they’ve done.” The first image was from their first trip to Africa, just after they had been engaged.

Melinda Gates: Bill had never taken that much time off work. We went to see the animals and the savanna, but what struck us most were the people, and the poverty. We started to talk about what might we do and how might we go about it?

Bill Gates: We were excited that there’d be a phase of our life where we’d get to work together and figure out how to give this money back. We were talking about the poorest, how could you have a big impact on them? There was a lot we didn’t know. Our naiveté was incredible when we look back on it.

MG: In 1997 we read an article about diarrhea killing so many kids. We said to ourselves, that can’t be. In the US you just go into a drug store. So we started gathering scientists and learning about what had worked and what failed.

CA: How do you decide what to focus on?

BG: The biggest inequity globally and countries that were really stuck . We started looking at children in poverty, children dying. Kids were so sick they couldn’t be educated and lift themselves up.

Anderson had also asked each to pick an infographic that illustrated their work. Melinda’s was about access to birth control.

MG: One of the things I love to do when I travel is go out into rural areas and talk to the women. I would want to talk about vaccines, and they would always bring the conversation around to “the shot I get,” Depo-Provera [a contraceptive].

Condoms were fully stocked in Africa because of the AIDS work the US and others supported. But the women said, “I can’t negotiate a condom with my husband. I’m either saying he has AIDS or I have AIDS.” So they walk for 10 kilometers to get the shot, and they get to the clinic and it’s stocked out.

CA: Melinda, you’re a Roman Catholic and you’ve been embroiled in controversy on this issue and the abortion question. How do you navigate that?

MG: That’s a really important point. We had backed away from contraceptives as global community. We knew 210 million women were saying they wanted access to contraceptives. We weren’t providing them because of political controversy in our country. To me, that was just a crime. I finally realized I had to do it. Even though I’m a Catholic, I believe in contraceptives, just like most Catholics.

There is a large round of applause on this point.

Bill’s infographic is about child mortality.

BG: My graph has numbers on it. I like this graph. This is the number of children that die before the age of 5 every year. Around when I was born we were at 20 million. We’re down to about 6 million. This is a story largely down to vaccines. You want that to continue. The science is there. If we can invent the vaccines, get them out there, and get the delivery right, you can perform a miracle.

98% of this has nothing to do with natural disasters. People’s charity when people see a natural disaster is wonderful. These causes have been a bit invisible. The Millennium Development Goals are getting out there, and we are seeing increased generosity. Our goal is to get this below a million.

CA: Conventional wisdom says it’s hard for married couples to work together. How do you do it?

MG: We enjoy it. I know when I come home, Bill is going to be interested in what I learned. And he knows when he comes home I’ll be interested. We have a collaborative relationship, but we don’t spend every minute together.

CA: Was it hard when Bill came on full-time at the foundation?

MG: For the employees there was more angst than for me. For me, the excitement about Bill putting his brain and his heart into this problem was exciting.

CA: What do you argue about?

BG: Because we built this thing together from the beginning, it’s a great partnership. We talk a lot about which things we should give more to, which groups are working well. There’s a lot of collaboration. I can’t think where one had super strong opinion about one thing or another.

MG: We come at things from different angles, and I think that’s really good. Bill can look at the data and say, “I want to come at it based on these statistics.” I talk to a lot of people, and ask, “Can you get a woman to accept those polio drops in her child’s mouth?” The delivery is every bit as important as the science.

CA: Are there failures you’ve learned from?

BG: We were very naive about a drug for leishmaniasis. It turns out it took an injection a day for ten days. There was no way it would get out there. So we spent, you could say wasted, five years and $60 million on a path that had a very modest benefit.

CA: And you’re spending like a billion every year on education?

MG: In the beginning we thought small schools were the answer. They definitely help, they bring down dropout rate, produce less crime in those schools. But what turned out to be the fundamental key is having a great teacher in front of the classroom. If you don’t have a great teacher in front of the building I don’t care how big or small the school is.

CA: Bringing up three children when you’re the world’s richest family seems like a social experiment without much prior art.

BG: To be clear, most of the money is going to the foundation. I’d say overall, the kids get a great education. So far they’re diligent, and excited to pick their own direction.

Anderson notes that the Gates have been protective of their family’s privacy, and asks why he has permission to show a photo of the family here at TED.

MG: As they get older they’ve been getting a sense that our family belief is about responsibility. They care deeply about the mission of the foundation. They want people to know that we believe in what we’re doing, and they gave us permission to show this picture.

CA: Is your plan to make them all billionaires?

BG: Nope. They need to have a sense their own work is meaningful and important.

CA: In 2006 Warren Buffet suddenly announced he was giving away 80% of his wealth. How did that happen?

BG: Warren was a close friend. He was going to have his wife Suzie give it all away. Tragically she passed away before he did. He’s big on delegation, and he said if he’s got somebody who’s doing something well and willing to do it at no charge… We were stunned, we never expected it.

CA: When you’re done, 90% of your wealth will be given to the foundation, yes?

BG & MG: Yes.

A large round of applause from the audience.

CA: As you’re trying to convince others to do similarly, how is that going?

BG: We have about 120 people signed on to the Giving Pledge, to give more than half of their assets to philanthropy. We’re not trying to homogenize. The beauty of philanthropy is this mind-blowing diversity.

MG: These are brilliant people. If they put their own minds behind philanthropy, that’s incredible.

CA: So, what’s the pitch?

BG: It’s the most fulfilling thing we’ve ever done. You can’t take it with you. If it’s not good for your kids, let’s get together and brainstorm what can be done. Part of the reason I’m so optimistic is I think philanthropy is going to grow and work on things government is just not good at shining a light on.

CA: There is a terrible inequality problem that seems structural. If more of your peers sign on, will that help?

BG: Yes. If you take from the most wealthy and give it to the least wealthy, that’s good.

MG: But you also change systems. We’re trying to change the education system so it’s just for everybody and it really works. That really changes the inequality balance.

So what went down at TED on day two? Well, a lot, as it happens. As curator Chris Anderson commented rather tiredly later, “that was the most intense day of TED I can remember, ever.” Here, a lightning round-up of some of the day’s key moments. Edward Snowden trundles onto stage The first big surprise […]

TED2014, our 30th anniversary conference, is less than a month away! If you’re counting the days like we are, get a head start by reading some of the insightful and compelling books by the groundbreaking thinkers who will speak in Vancouver. Books from speakers in Session 1, “Liftoff” Being Digital, by Nicholas Negroponte. This 1995 […]